The agency on Thursday released an e-mail from Snowden to the NSA's general counsel showing the former government contractor asking to clarify a training document. Nowhere in the e-mail were any surveillance concerns raised.

After including a list from “The Hierarchy of Governing Authorities and Documents,” Snowden requested clarification as to whether and executive order would take precedence over a federal statute. He also asked whether Department of Defense regulations took precedence over the Office of the Director of National Intelligence regulations.

The e-mail is dated April 5, 2013, four months after he apparently first contacted journalist Glenn Greenwald and three months after reaching out to documentary filmmaker Laura Poitras. The e-mail was also sent nearly a year after Snowden first began illegally downloading NSA documents, according to NSA Deputy Director Rick Ledgett.

Snowden, in a taped interview with NBC host Brian Williams that aired Wednesday, said that the NSA had evidence that he went through proper channels.

“The NSA has records, they have copies of e-mails right now — to their office of general counsel, to their oversight and compliance folks — from me, raising concerns about the NSA’s interpretations of its legal authorities,” Snowden said.

But if it's true that the e-mail released Thursday is the only one Snowden sent to the general counsel, it could be a big blow to his credibility.